Conventionally, there are various proposals for a seal of a housing through which a signal line such as a flexible cable or a circuit portion passes. For example, a recess step is provided at least one of joining surfaces of first and second housings, and first and second seal members and the signal line or the circuit portion are sandwiched by the first and second housings at the recess step (See Japanese Examined Patent Publication No. 2009-26966). In this proposal, the passing of the signal line and the circuit portion and the maintenance of the hermetic property are achieved by the adherence and flexibility of the first seal member and the stretchability of the second seal member. In such a conventional proposal, the first seal member may be discontinuous foam or include discontinuous foam.
The discontinuous foam has good stretchability in its thickness direction. However, the discontinuous foam has poor stretchability in its width direction. For this reason, when the signal line such as a cable is thick, the deformation of the discontinuous foam may not follow the thickness of the signal line and possibly generate a gap in the seal portion. These days, as for s flat cable as an example of the signal line, multiple flat cables are assumed to be used with being stacked each other. When the multiple flat cables are stacked to increase the entire thickness, the conventional proposal may not ensure a sufficient seal property.